Commit 7797dc41 authored Feb 27, 2018 by Soheil Hassas Yeganeh Committed by David S. Miller Mar 01, 2018

socket: skip checking sk_err for recvmmsg(MSG_ERRQUEUE)



recvmmsg does not call ___sys_recvmsg when sk_err is set.
That is fine for normal reads but, for MSG_ERRQUEUE, recvmmsg
should always call ___sys_recvmsg regardless of sk->sk_err to
be able to clear error queue. Otherwise, users are not able to
drain the error queue using recvmmsg.

Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 96dbdc5d

net/socket.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -2289,11 +2289,13 @@ int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
		if (!sock)
		return err;

		if (likely(!(flags & MSG_ERRQUEUE))) {
		err = sock_error(sock->sk);
		if (err) {
		datagrams = err;
		goto out_put;
		}
		}

		entry = mmsg;
		compat_entry = (struct compat_mmsghdr __user *)mmsg;